A lot of work has gone into making Vue Pro as responsive as possible (there are a lot of threads working in the background to avoid slowing down the application). The downside to this approach is that you may not realize how complex your scene is becoming.
Here are a couple of general recommendations to lessen the burden on the processor/memory:

• disable the automatic scene preview. Click on it when you want to see a render.
• reduce the quality of the OpenGL views.
• in the view options, select the option to only display the objects from the active layer.
• disable the background draw thread.
• reduce the number of Undo/Redo operations to 1.
• disable the option to decimate objects upon import (that's in the options dialog).
• Enable the option to only render the material preview in the active editor (also in options dialog).

Most of all, keep an eye on your memory usage.

Djeser, the scene saving code hasn't been modified. I think that what you are experiencing is memory saturation and the OS swapping. You should get in touch with tech support to try and find a solution.

Hope that helps.